This application relates to blow-molded containers, and more particularly to hot-fillable containers having integral grip portions formed therein.
Perishable beverage and food products are often placed into containers at elevated temperatures. In a conventional hot-fill process, the liquid or flowable product is charged into a container at elevated temperatures, such as 180 to 190 degrees F, under approximately atmospheric pressure. Because a cap hermetically seals the products within the container while the products are at the hot-filling temperature, hot-fill plastic containers are subject to negative internal pressure (that is, relative to ambient pressure) upon cooling and contraction of the products and any entrapped air in the head-space.
It has been an inherent goal of conventional hot-fill container design to form stiff cylindrical portions (in transverse cross section) that maintain a cylindrical shape upon cooling. Thus, conventional hot-fill containers include designated flexing portionsxe2x80x94vacuum panelsxe2x80x94that deform when subject to typical hot-fill negative internal pressures. The inward deflection of the vacuum panels tends to equalize the pressure differential between the interior and exterior of the container so as to enhance the ability of the cylindrical sections to maintain an attractive shape, to enhance the ease of labeling, or like commercial appeal. Some container designs are symmetric about a longitudinal centerline and designed with stiffeners to maintain the intended cylindrical shape while the vacuum panels deflect. For example, U.S. Pat. Nos. 5,178,289, 5,092,475, and 5,054,632 teach stiffening portions or ribs to increase hoop stiffness and eliminate bulges while integral vacuum panels collapse inwardly. U.S. Pat. No. 4,863,046 is designed to provide volumetric shrinkage of less than one percent in hot-fill applications.
Other containers include a pair of vacuum panels, each of which has an indentation or grip portion enabling the container to be gripped between a user""s thumb and fingers. For example, U.S. Pat. No. 5,141,120 teaches a bottle having a hinge continuously surrounding a vacuum panel, which includes indentations for gripping. In response to cooling of the container contents, the hinge enables the entire vacuum panel to collapse inwardly. U.S. Pat. No. 5,141,121 similarly teaches a bottle having an outward bulge that inverts in response to cooling of the container contents. Each of the patents referred to herein by patent number is incorporated by reference in its entirety.
Some hot-fill technology employs charging the product under atmospheric pressure (that is, gravity filling). However, metering the products under a positive pressure pumping system has been found to increase the accuracy and precision of the product volume charged into the container. Such positive pressure filling systems enable better accuracy and precision of the predetermined product volume, better control of the headspace volume, and other benefits. The metering typically subjects the container to a positive pressure (relative to ambient pressure) of a few PSI during charging. Typical charging pressures may be 1 to 2 PSI, although 5 PSI or greater may be encountered in certain circumstances. After filling, the pressure is typically released by exposing the contents to approximately atmospheric pressure prior to capping. It is a goal to provide improved containers.
Conventional containers often include stiffeners to enhance the stiffness of portions thereof. Some containers even have stiffeners within the vacuum panels themselves. It has been found that stiffened containers may have a tendency to form a crease or kink in the container sidewall upon being subjected to the positive pressures inherent in pressure filling technology and techniques. In this regard, the sidewall forms an undesirable outer bulge or crease, thereby weakening the sidewall. Further, sometimes the sidewall crease does not snap back towards a cylindrical shape upon pressure release. Thus, stiffeners intended to maintain a cylindrical container shape or resist distortion, in some circumstances, may result in a container that is overly stiff and subject to creasing, and the stiffeners tend to inhibit the creased sidewall from snapping back upon pressure release.
A hot-fillable container formed by blow molding a thermoplastic is provided. The container comprises a neck portion, an enclosed bottom portion, and a body portion. The body portion is disposed between the neck portion and the bottom portion and includes a substantially cylindrical front segment, a substantially cylindrical rear segment opposite the front segment, and a pair of opposing handgrips disposed therebetween.
Each one of the handgrips includes a relatively stiffened boundary that resists deformation upon internal vacuum conditions and a relatively un-stiffened boundary. The relatively unstiffened boundary is disposed opposite from the relatively stiffened boundary and non-parallel thereto such that a portion of the handgrip forms a thumb piece. The panels are joined to said rear segment of the body portion without hinges so as to promote inward deformation of portions of the rear segments proximate the panels upon internal vacuum conditions. A rear portion of each one of the panels may be joined to the rear segment of the body portion without a hinge. The handgrips may be hingeless. The handgrip may have a depth that is greater proximate the relatively stiffened boundary than proximate the relatively unstiffened boundary. Each one of the panels may be formed by a shim-able insert such that the bottle volume is adjustable. Each one of the panels includes a handgrip formed therein.
Preferably, after deforming upon hot-filling, capping, and cooling, the bottle deforms less than approximately 2.0 mm at any location on the bottle compared with dimensions after blow-molding. Such deformation may be created upon filling of the container at a temperature up to approximately 220 degrees, above approximately 135 degrees F, between approximately 170 degrees F and approximately 195 degrees F, and/or between approximately 180 degrees F to approximately 195 degrees F.